Articles / Debian: cfingerd remote exp…

Debian: cfingerd remote exploit

Steven van Acker reported on bugtraq that the version of cfingerd (a configurable finger daemon) as distributed in Debian GNU/Linux 2.2 suffers from two problems: The code that reads configuration files (files in which $ commands are expanded) copied its input to a buffer without checking for a buffer overflow. When the ALLOW_LINE_PARSING feature is enabled that code is used for reading users files as well, so local users could exploit this. Also, there also was a printf call in the same routine that did not protect against printf format attacks. Since ALLOW_LINE_PARSING is enabled in the default /etc/cfingerd.conf local users could use this to gain root access. Both problems have been addressed in version 1.4.1-1.2 which is available from security.debian.org.
-----BEGIN PGP SIGNED MESSAGE-----

- ------------------------------------------------------------------------
Debian Security Advisory DSA-066-1                   security@debian.org
http://www.debian.org/security/                         Wichert Akkerman
July 11, 2001
- ------------------------------------------------------------------------


Package        : cfingerd
Problem type   : remote exploit
Debian-specific: no

Steven van Acker reported on bugtraq that the version of cfingerd (a
configurable finger daemon) as distributed in Debian GNU/Linux 2.2
suffers from two problems:

1. The code that reads configuration files (files in which $ commands are
   expanded) copied its input to a buffer without checking for a buffer
   overflow. When the ALLOW_LINE_PARSING feature is enabled that code
   is used for reading users files as well, so local users could exploit
   this.

2. There also was a printf call in the same routine that did not protect
   against printf format attacks.

Since ALLOW_LINE_PARSING is enabled in the default /etc/cfingerd.conf
local users could use this to gain root access.

This has been fixed in version 1.4.1-1.2, and we recommend that you upgrade
your cfingerd package immediately.

wget url
        will fetch the file for you
dpkg -i file.deb
        will install the referenced file.


Debian GNU/Linux 2.2 alias potato
- ---------------------------------

  Potato was released for alpha, arm, i386, m68k, powerpc and sparc.

  Source archives:
    http://security.debian.org/dists/stable/updates/main/source/cfingerd_1.4.1-1.2.diff.gz
      MD5 checksum: e1e5ed3fe85f2af5304b9f0d3d236a91
    http://security.debian.org/dists/stable/updates/main/source/cfingerd_1.4.1-1.2.dsc
      MD5 checksum: 966e205737bcd43182d01114694ed52a
    http://security.debian.org/dists/stable/updates/main/source/cfingerd_1.4.1.orig.tar.gz
      MD5 checksum: 0461179bca7bb9b00fb23c0886666cb0

  Alpha architecture:
    http://security.debian.org/dists/stable/updates/main/binary-alpha/cfingerd_1.4.1-1.2_alpha.deb
      MD5 checksum: 9c43dd39460c58ed6a0134333349e2f9

  ARM architecture:
    http://security.debian.org/dists/stable/updates/main/binary-arm/cfingerd_1.4.1-1.2_arm.deb
      MD5 checksum: 70da6073d42fbbdd29a025517127ebb0

  Intel IA-32 architecture:
    http://security.debian.org/dists/stable/updates/main/binary-i386/cfingerd_1.4.1-1.2_i386.deb
      MD5 checksum: 2281e1aa8dc439680b1df546a5139aae

  Motorola 680x0 architecture:
    http://security.debian.org/dists/stable/updates/main/binary-m68k/cfingerd_1.4.1-1.2_m68k.deb
      MD5 checksum: 19bf9fbcf1d2e1d7d38ff5bd00c6dc0a

  PowerPC architecture:
    http://security.debian.org/dists/stable/updates/main/binary-powerpc/cfingerd_1.4.1-1.2_powerpc.deb
      MD5 checksum: 383389307d0ebd11b3f8a20abe1395a9

  Sun Sparc architecture:
    http://security.debian.org/dists/stable/updates/main/binary-sparc/cfingerd_1.4.1-1.2_sparc.deb
      MD5 checksum: 1e734a8573e1c05d8e07ffcc8543c4e9

  These packages will be moved into the stable distribution on its next
  revision.

For not yet released architectures please refer to the appropriate
directory ftp://ftp.debian.org/debian/dists/sid/binary-$arch/ .

- -- 
- ----------------------------------------------------------------------------
apt-get: deb http://security.debian.org/ stable/updates main
dpkg-ftp: ftp://security.debian.org/debian-security dists/stable/updates/main
Mailing list: debian-security-announce@lists.debian.org

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